Purpose: To examine the associations of alcohol consumption in different periods of pregnancy with the risks of low birth weight and preterm birth.
Methods: This study was based on 7141 subjects participating in a population-based prospective cohort study from early pregnancy. Alcohol consumption was assessed in early, mid, and late pregnancy. Birth outcomes were birth weight in grams, low birth weight (<2500 g), small size for gestational age at birth (< -2 standard deviation scores) and preterm birth (gestational age <37 weeks).
Results: Overall, alcohol consumption during pregnancy was not associated with adverse birth outcomes. However, dose-response analyses showed tendencies toward adverse effects of average consumption of 1 or more alcoholic drinks per day in early pregnancy on birth weight (difference -129 g [95% confidence interval (CI): -271, 12]), low birth weight (adjusted odds ratio [aOR] 4.81 [95% CI: 1.10, 21.08]), small size for gestational age at birth (aOR 1.45 [95% CI: 0.33, 6.44]) and preterm birth (aOR 2.51 [95% CI: 0.92, 6.81]). Similar effects were found in late pregnancy.
Conclusion: Average consumption of one or more but not less than one alcoholic drink per day in early or late pregnancy seems to be associated with adverse birth outcomes in the offspring.